The first step in what they call "the Rabbit Illusion" is to stare at the cross at the top of the screen. While doing that, you'll hear a few ticking sounds and see a few flashes. But the question is, how many flashes do you see?

Give it a try:

While most people see three flashes when the sound is playing, there are actually only two. The trick is in the sound. Since there were three ticking sounds, your mind creates a third flash to match, which is called an "illusory flash."

There were actually only two flashes, but there are three beeps.Caltech/ Youtube

Caltech says this is proof that our senses can influence each other.

With this illusion, researchers believed they demonstrated how sound can influence our vision. They call it postdiction, which means "a stimulus that occurs later can retroactively affect our perceptions of an earlier event."